Beverage containers, particularly rigid walled ones, such as juice containers, soda bottles, wine bottles, or the like, are often filled from a pressurized, liquid containing bowl of a filling machine. Although the invention is hereafter described in connection with beverage containers, it is not thus limited and is applicable to any liquid in any type of container, so long as the container is filled under pressure from a pressurized source, like a bowl. The pressurized bowl has a plurality of filling valves communicating into it. Each filling valve is alternately connected to and disconnected from an individual container. The bowl is pressurized in order to speed the filling of the individual beverage containers, without significant interference to the flow due to the viscosity of the liquid, the narrow width of the filling orifice or other well-known impediments to rapid filling of a container.
The entrance to each filling valve is located inside the pressurized bowl and its exit is outside the pressurized bowl. Conventional filling valves are, therefore, designed to prevent leakage of pressurized liquid from the filling bowl when a bottle or container is not present. The filling valves also include means that prevents exit of pressurizing gas from the filling valve when a container is not present.
For control of liquid undesirably leaking through the filling valve, conventional filling valves include an axially shiftable piston having a valve element thereon. The valve element is raised off a valve seat to open the liquid feeding orifice leading to the container being filled, but the liquid flow blocking valve element is normally urged against the valve seat to close the feeding orifice when a container to be filled is not present.
Conventional filling valves are cam operated between their liquid flow blocking and permitting positions. Control means external to the bowl operate the cam between the filling valve positions in appropriate sequence coordinated with the presence or absence of the container to be filled.
Conventional filling valves also include a separate gas flow passage communicating between the gas under pressure inside the bowl through the filling valve and extending down so as to be insertable in the container to be filled. In a typical beverage filling valve of the type to which the present invention applies, the gas filling conduit is a tube and the liquid flows into the container outside the tube. An appropriate cover or capping means over the top of the tube is selectively opened or closed in timed sequence to permit gas to escape through the tube into a container or to prohibit such escape. The same cam that controls the positions of the liquid flow valve element also caps or uncaps the gas flow tube. So long as a container is properly placed at a filling valve during each filling cycle, the cam controlled means opens both the liquid flow valve and the gas flow tube in timed sequence and causes them to be reclosed in proper timed sequence.
When a container to be filled is present, and both the gas flow conduit and the liquid flow valve are open, and if the container is removed, for example by breaking, in the conventional filling valve, different things occur with the liquid and the gas flows.
With the container suddenly absent, a great liquid pressure differential develops between the interior of the pressurized bowl in which the liquid flow valve element of the filling valve is located and the exterior of the pressurized bowl in the immediate vicinity of the liquid flow valve element. This pressure differential urges liquid to flow rapidly out of the filling valve and the force of the liquid trying to flow out the valve and past the flow valve element, coupled with the great pressure differential on the flow valve element itself, immediately urges the flow valve element to its closed position, cutting off liquid flow.
However, the gas will continue to exit through the gas flow conduit of the valve until such time in the cycle as the cover on the gas flow is reclosed to its flow blocking position by the closing cam.
Various arrangements have been attempted for sensing the pressure drop at the outlet end of the gas flow conduit when a container is suddenly absent and for causing this sensed pressure drop to activate the cover to close the inlet to the gas flow conduit. However, such means have not operated effectively, and there is continuous gas escape from the pressurized bowl through the gas flow conduit until the closing cam in due time during the cycle mechanically recloses the cover over the opening into the gas flow conduit. Effective means are thus required for closing the gas flow conduit if, suddenly, no container is present to receive liquid through the filling valve.